Damian Thompson is Editor of Telegraph Blogs and a columnist for the Daily Telegraph. He was once described by The Church Times as a "blood-crazed ferret". He is on Twitter as HolySmoke. His latest book is The Fix: How addiction is taking over your world. He also writes about classical music for The Spectator.

What I said to the taxi driver who thought 9/11 was an inside job

In a taxi cab in Soho this evening, I noticed that the balding hippy driver was displaying a sign in the back that read: "9/11 was an inside job".

I thought about defacing it, but opted for a simpler solution. "What's with the 9/11 sticker?" I asked the cabbie as I got out.

"I put that there," he said smugly. "Does it disturb you?'

"No," I said, handing over the exact fare. "But no tips for liars."

Petty? Maybe. But I felt cross enough to tweet about it, and back came a message of thanks from a complete stranger – Gabrielle Laine-Peters, a social media entrepreneur who spent years recovering from injuries received at the World Trade Centre when it was destroyed by Islamist terrorists.